package api;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.mysql.jdbc.Connection;
import lombok.SneakyThrows;
import model.Article;
import util.AppVar;
import util.DBUtils;
import util.ResultUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

/**
 * @author shkstart
 * @create 2023-01-17-22:02
 */
@WebServlet("/artlist")
public class ArticleListServlet extends HttpServlet {
    @SneakyThrows
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        List<Article> data = new ArrayList<>();
        String msg = "未知的参数";
        //1.得到参数并校验
        String currPage = req.getParameter("cp");
        String pageSize = req.getParameter("ps");
        int cp = 1;//当前的页码
        int ps = 2;//每页显示的最大条数
        if(!StrUtil.isBlank(currPage)){
            cp = Integer.valueOf(currPage);
        }
        if(!StrUtil.isBlank(pageSize)){
            ps = Integer.valueOf(pageSize);
        }

        //2.使用分页查询，查询数据库得到结果
        Connection connection = DBUtils.getConnection();
        String sql = "select * from article order by aid desc limit ? offset ? ";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setInt(1,ps);
        statement.setInt(2,(cp-1)*ps);
        ResultSet resultSet = statement.executeQuery();

        while (resultSet.next()){
            Article article = new Article();
            article.setAid(resultSet.getInt("aid"));
            article.setTitle(resultSet.getString("title"));
            String ctime = resultSet.getString("createtime");
            article.setCreatetime(ctime.substring(0, ctime.lastIndexOf(".")));
            String context = resultSet.getString("context");
            context =context.replace("#","");
            int maxSize = Integer.min(50,context.length());
            article.setDesc(context.substring(0,maxSize));
            data.add(article);
        }

        msg = "成功抵达articlelist";
        DBUtils.close(resultSet,statement,connection);
        //3.将数据返回改前端
        resp.setContentType(AppVar.RESP_JSON_UTF8);
        resp.getWriter().println(
                JSONUtil.toJsonStr(
                        ResultUtils.toResult(200,data,msg)
                )
        );
    }
}
